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Record the effect that the enzyme catalase found inside the potato has, when added to hydrogen peroxide, and whether to not there is a change in the rate of reaction when the surface area of the potato is increased.

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PLANNING Enzymes Background Information Enzymes such as catalyse are protein molecules, which are found in living cells. They are used to speed up specific reactions in the cells. They are all very specific as each enzyme just performs one particular reaction. Catalyse is an enzyme found in food such as potato and liver. It is used for removing Hydrogen Peroxide from the cells. Catalyse speeds up the decomposition of Hydrogen Peroxide into water and oxygen. It is able to speed up the decomposition of Hydrogen Peroxide because of the shape of the Hydrogen Peroxide molecule. This type of reaction where a molecule is broken down into smaller pieces is called an anabolic reaction. Aim: Carry out an experiment on enzyme activity. The aim is to record the effect that the enzyme catalase found inside the potato has, when added to hydrogen peroxide, and whether to not there is a change in the rate of reaction when the surface area of the potato is increased. Apparatus: Apparatus * Hydrogen peroxide (H202) of 20 volume * Ruler * Measuring cylinder 150ml * Potato * Stop watch * Goggles * Beakers of various sizes Arrangement of our experiment: Fair Test We must ensure that the experiment is a fair test. To do this we are going to take use of the same apparatus. The only variables to be changed is the surface area of the potatoes and we will repeat the investigation two times. ...read more.


Enzymes are the catalysts in biological processes. They are large proteins that speed up chemical reactions. The enzyme forms the active site from small numbers of amino acids. The active site is the location on the enzyme where the substrate collides and the reaction takes place. If the shape of and the substrate do not match exactly then they do not bind. This makes sure that the enzyme does not work with the wrong reaction. Enzymes are not affected by the reaction, so when the products have been released, the enzyme is ready to bind with a new substrate. In my experiment the substrate was the hydrogen peroxide, the enzyme that we used was hydrogen peroxide and the product that was formed was oxygen and water. This can be explained by an equation: Enzyme + Substrate � Product In my experiment this is shown as: Catalase + H202� H202 + 02 This equation explains how the catalase in our experiment binded with the H202 to break it down and form oxygen. Induced Fit Theory The induced fit theory states that the binding of a substrate to an enzyme causes a change in the shape of the enzyme. The enzyme and the substrate act on each other to affect the making of the active site to the usual complex between the enzyme and its substrate. As a result, this means the enzyme to catalyze a reaction has changed. This shows that enzymes are specific for specific substrates. ...read more.


I will keep constant are: -Amount of hydrogen peroxide - Temperature of the hydrogen peroxide - Concentration of the hydrogen peroxide - Mass of the piece of potato - Type and age of the potato - Apparatus used The above list of controlled variable will ensure I have a fair test to give accurate results. And I will repeat the experiment again to make sure. So to sum it up the variables, what will be measured, is due to the change surface area. Thus I have made a plan set fourth in accordance to all the information above: 1) Collect all the right apparatus. 2) Set the experiment in a free space zone area. 3) Cut the potatoes to the various sizes from the received 4cm potato. 4) Measure out 20cm3 of hydrogen peroxide by using a measuring cylinder. 5) Receive test tube and pure in the hydrogen peroxide and the various potato sizes. 6) Wait for four minutes. 7) Then get a ruler. 8) Measure the length of the froth. 9) Afterwards, dispose of the potato into a bin, and clear the surfaces you have worked on. 10) Repeat for all left sizes. This is the method I am going to use for every potato size. By carrying out all the things, which I have listed, I will be able to establish precisely that my test has been fair. I will be able to prove this by saying all materials and apparatus have been handled and used with the same treatment, and in an overall fair manner. ...read more.

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